Figure 6. The primed and IL-1β signature of monocytes recruited to the brain during stress was dependent on IL-6.

Male WT and IL-6^KO C57BL/6 mice were subjected to six repeated cycles of social defeat (Stress) or left undisturbed as controls (n=5). (A) 14 h later, monocytes (CD11b⁺/CD45^hi) in the brain were collected and FAC-sorted. Next, RNA was isolated and mRNA copy number of 279 genes was determined using NanoString gene array. Volcano plot (-log₁₀ (p value) vs. fold change) of genes differentially expressed between brain monocytes from (B) WT stress and WT control groups, (C) IL-6^KO stress and WT-stress groups, and (D) IL-6^KO stress and IL-6^KO control groups. Genes labeled in red (increased) and blue (decreased) were significantly different. (E) Pathways regulated by stress in the wildtype and IL-6^KO brain monocytes after stress. (F) Venn diagram depicts genes significantly altered between WT Stress and WT Control but not between IL-6^KO Stress and WT Stress (black background), genes significantly altered between WT Stress and WT Control and between IL-6^KO Stress and WT Stress (grey background), and genes significantly altered only between the IL-6^KO stress and WT stress (p < .05 for all).